Preheat oven to 180C fan-forced. Line a baking tray with baking paper.
Place bacon in a single layer and brush with maple syrup. Cook for 20 minutes or until crisp.
Place egg yolk, milk, 60g melted butter and flour together in a medium bowl and whisk to combine. Whisk egg whites and sugar in a small bowl until light and fluffy and gently fold into flour mixture.
Preheat a waffle iron. Using ¼ cup of the waffle batter at a time. Cook for 4 minutes or until golden.
Melt remaining butter in a large frying pan over medium high heat. Add mushrooms and chives. Season with salt and pepper. Cook, stirring occasionally for about 5 minutes or until mushrooms are lightly golden.
Place waffles on serving plates. Top with maple bacon, Mushrooms, sour cream and chives.